Aqueous dispersion based on viscous silicone oils crosslinkable by condensation into an adhering elastomer for use in particular as sealants or paints, preparation method

ABSTRACT

The invention concerns an aqueous dispersion of viscous silicone oils capable of being crosslinked into an elastomer by water elimination (condensation). The invention aims at obtaining an aqueous silicone dispersion corresponding to an optimal compromise in terms of adherence of the crosslinked elastomer on all types of supports, and the colloidal stability of the dispersion during preparation and storage. Said aqueous dispersion comprises a viscous silicone oil A, optionally a crosslinking agent B, optionally an adhesion promoter C (silane), a filler D, a catalyst E, an emulsifier F, optionally a functional additive G and water. Said dispersion is characterised in that the filler D is input into the process for obtaining the dispersion, in the form of an aqueous suspension of at least a hydrophilic compound (CaCO3SiO2, TiO2, Al2/H2O, organic polymer latex). The invention also concerns the preparation of said particularly stable dispersion since it has a residual emulsion rate T not less than 70%. The invention is useful for producing concentrated sealants and elastomer coating for insulating polymer foam (polyurethane).

This application is an application under 35 U.S.C. Section 371 ofInternational Application Number PCT/FR01/02105 filed on Jun. 29, 2001.

The present invention relates to a novel aqueous dispersion based onviscous silicone oils that may be crosslinked into an elastomer byremoval of water (condensation). This crosslinked elastomer may be usedto produce mastics or any other sealing material, or alternativelyflame-retardant or water-repellent elastomeric coverings and coatings,which may be sprayable, eg: paints and flexible semi-thick coverings.

The present invention is also directed toward the preparation of thisaqueous silicone dispersion.

Conventionally, aqueous dispersions of silicone oils comprise:

-   A—at least one polyorganosiloxane oil capable of crosslinking into    an elastomer by condensation and removal of water;-   B—optionally at least one crosslinking agent;-   C—optionally at least one adhesion promoter preferably consisting of    at least one silane;-   D—a siliceous or nonsiliceous organic and/or mineral filler;-   E—optionally a curing catalyst (tin-condensation catalyst);-   F—at least one emulsifier (ionic or nonionic surfactant);-   G—one or more other functional additives;-   H—and water.

These aqueous silicone dispersions that may be crosslinked into anelastomer by condensation with removal of water or alcohol are easy touse, especially in construction, on account of their water-washablenature.

However, these products have raised a certain number of technicaldifficulties;

-   stability on storage (degree of coalescence),-   excessively long curing time,-   mediocre mechanical properties of the elastomer (hardness,    elasticity, abrasion resistance),-   lack of thixotropy of the elastomer,-   lack of “combable” nature of the elastomer,-   problem of safety and toxicity due to the solvents and alcohols    formed by hydrolysis,-   low adhesion and cohesion properties of the elastomer to the usual    supports,-   stability of emulsion during formulation and storage (degree of    coalescence),-   ease of emulsification and of formulation of the dispersion,-   possibility of continuous preparation depending on the industrial    constraints.

Among all these specification details, there is one that is particularlyimportant for assessing the quality of an aqueous silicone dispersion.This is the adhesion of the elastomer formed from the aqueous siliconedispersion after evaporation of the water or even the alcohol ofcondensation. The desired adhesion for the elastomer should beunderstood both in terms of adhesion strength on a given support and interms of adhesion to a wide range of different supports (glass, wood,metal, concrete, PVC and polyurethane). The search for adhesion is allthe more difficult since it is generally performed to the detriment ofthe colloidal stability of the dispersion.

Perfectible aqueous silicone dispersions are thus known, especially asregards improving the adhesion.

American patent U.S. Pat. No. 4,221,688 discloses an aqueous siliconedispersion capable of forming an elastomer by condensation/drying. Thisdispersion is obtained by emulsion polymerization, which requires theuse of an anionic surfactant for stabilization. Among the fillersincorporated into this aqueous silicone dispersion is an aqueousdispersion of colloidal silica.

The necessary presence of an ionic surfactant, usually an anionicsurfactant, is harmful to the stability of the aqueous siliconedispersion (mastic). It reduces its performance qualities, for exampleas regards the adhesion and the mechanical properties. The aqueousdispersions obtained by the process according to the patent have a lowconcentration and low stability, in particular in a freezing/thawingcycle.

The low adhesion of the elastomers obtained from theseemulsion-polymerized aqueous silicone dispersions is linked to the highconcentration of surfactants. This method of production by emulsionpolymerization should be distinguished from the preparation of aqueoussilicone dispersions according to an operating protocol involving anemulsification of an already-polymerized silicone, an optional dilutionof the emulsion and a formulation of the dispersion (“compounding”).

The said American patent does not address, and with reason, the use ofcolloidal silica during the emulsification.

It should moreover be added that this technique is restrictive andrelatively uncompetitive.

European patent applications EP 0 665 861 and EP 0 665 862 describe thepreparation of a mastic made of an aqueous silicone dispersion, byemulsification of a viscous reactive silicone oil optionally containinga crosslinking agent (for example a hydroxylated silicone resin), acatalyst and a filler incorporated in pulverulent form (for exampleprecipitated and coated calcium carbonate), and also a nonionicsurfactant (polyethoxylated nonylphenol), optionally adhesion promotersof the alkoxylated silane type (vinyltrimethoxysilane,N-methyl-3-aminopropyl-trimethoxysilane,N-aminoethyl-3-aminopropyltrimethoxy-silane or3-aminopropyltriethoxysilane) and, naturally, water introduced duringthe emulsification into the viscous phase.

The aqueous silicone dispersions according to said patents are prepared,precisely, according to a principle of emulsification in concentratedphase, with mixtures of water and structured surfactants having a highviscosities.

These aqueous dispersions, based on α,ω-functional viscous siliconeoils, are stable on storage (fine particle size and absence of anionicsurfactants) and are capable of crosslinking by elimination of water, oreven of alcohol, into an elastomer whose mechanical properties aresatisfactory. These dispersions contain a dispersed silicone polymerwhose degree of polymerization is better controlled than that of apolymer obtained by emulsion polymerization.

Although having properties that are overall entirely respectable, theaqueous silicone dispersions described in said patents were open toimprovement as regards the adhesion/colloidal stability duringpreparation and storage compromise.

One of the essential objectives of the present invention is that ofsignificantly optimizing the abovementioned adhesion/stabilitycompromise.

Another essential objective of the invention is that of proposing anaqueous silicone dispersion that may be crosslinked into an elastomer byremoval of water, which overcomes the drawbacks of the analogousproducts according to the prior art.

Another essential objective of the invention is that of providing anaqueous silicone dispersion that has reduced concentrations ofsurfactants, without the colloidal stability of the dispersion beingaffected.

Another essential objective of the present invention is that ofproposing a silicone dispersion that may be obtained readily byemulsification, optional dilution and formulation (“compounding”).

Another essential objective of the invention is that of providing ahighly concentrated aqueous silicone dispersion.

Another essential objective of the invention is that of providing anaqueous silicone dispersion that may be obtained with equal ease inbatchwise mode or in continuous mode with industrial constraints.

Another essential objective of the invention is that of providing asimple and economical process for preparing an aqueous siliconedispersion of the abovementioned type.

Another essential objective of the invention is that of proposing aprocess for preparing the abovementioned dispersion, said processneeding to be applicable in batchwise mode and in continuous mode withindustrial constraints and while ensuring reliability under allcircumstances.

Another essential objective of the invention is that of providing anaqueous silicone dispersion whose adhesion and stability aresignificantly improved compared with the existing dispersions, and whichmoreover satisfies the abovementioned specification.

Another essential objective of the invention is that of providing anaqueous silicone dispersion that may be used for the manufacture ofconcentrated mastics, elastomeric coating products or water-repellent orflame-retardant protective coverings, which may be sprayable(“roofing”).

These objectives, among others, are achieved by the present invention,which relates firstly to an aqueous dispersion of silicone oil(s)comprising:

-   A—100 parts by weight of at least one polyorganosiloxane oil (A)    capable of crosslinking into an elastomer by condensation, if    necessary in the presence of a crosslinking agent (B);-   B—if necessary, from 0.1 to 100 parts by weight of at least one    crosslinking agent (B);-   C—optionally, up to 50 parts by weight of at least one adhesion    promoter (C)—preferably a silane—;-   D—up to 200 parts by dry weight of a filler (D);-   E—a catalytically effective amount of a catalytic curing compound    (E), which may be up to 3 parts by weight;-   F—at least one emulsifier (F);-   G—optionally, at least one functional additive (G);-   H—and water;    -   said dispersion being obtained:    -   by production of an emulsion by blending a mixture consisting        of:        -   100 parts by weight of a silicone phase (φs) with a dynamic            viscosity at 25° C. of at least 10 Pa.s, preferably 50 Pa.s            and even more preferably 70 Pa.s, φs comprising the oil or a            mixture of oils (A) already polymerized, and optionally at            least one of the constituents (B), (C) or (E);        -   0.5–20 parts by weight of at least one emulsifier (F), the            HLB value of said emulsifier or of the mixture of            emulsifiers being at least 10;        -   0–100 parts by weight of filler (D);        -   2–20 parts by weight of water;        -   the water/water+surfactant(s) weight ratio being such that            the viscosity of the water+surfactant(s) mixture is in the            region of or greater than half that of the silicone phase            (φs);        -   for a period and under shear conditions that are sufficient            to obtain an “oil-in-water” emulsion with a particle size            from about 0.1 to 5 micrometers;-   by optional dilution with water until a solids content from 25% to    97% is obtained;-   and then by addition    -   -   of the constituent(s) not present in the silicone phase (φs)        -   and/or of 0–100 parts by weight of filler (D);

    -   characterized        -   in that the filler (D) is supplied, in the process for            obtaining the dispersion, in the form of (an) aqueous            suspension(s) of at least one hydrophilic compound,        -   with the conditions according to which:            -   when the filler (D) supplied in the process for                obtaining the dispersion consists at least partly of at                least one aqueous suspension of colloidal silica, then                this (or these) aqueous suspension(s) of filler (D) is                (are) introduced in total into the blending chamber                before producing the emulsion;            -   and when the filler (D) supplied in the process for                obtaining the dispersion consists at least partly of at                least one aqueous suspension of organic (co)polymer(s),                then at least some of this (or these) aqueous                suspension(s) of filler (D) is (are) introduced into the                blending chamber before producing the emulsion.

This production characteristic, namely the use of a hydrophilic fillerpredispersed in water, makes it possible, entirely surprisingly andunexpectedly, to lower the dose of surfactants in the siliconedispersion and to improve the adhesion of the elastomer that may beobtained from said dispersion, without degrading the colloidal stabilityof the dispersion.

The colloidal stability of the dispersion is evaluated by means of theresidual emulsion content T (%) measured according to an operatingprotocol P defined below in example 1.

Furthermore, the use of a hydrophilic filler predispersed in water makesit possible to limit the coalescence under shear of the concentratedemulsion in the first step for preparing the dispersion according to theinvention.

The dispersion according to the invention also has the advantage ofbeing prepared according to a procedure that poses no particularpractical difficulties, especially as regards the emulsification.

In addition, the aqueous silicone dispersion according to the inventionmay be highly concentrated. Using a filler in aqueous dispersion ratherthan a powdered filler significantly improves the “processability” ofthe aqueous dispersions according to the invention, such that theircontinuous production is fully controlled.

The present invention may be likened to a selection of a hydrophilicfiller that is used in aqueous suspension during the preparation of thedispersion.

The inventors have, to their credit, made this selection which induces,against all expectation, particularly efficient characteristics in termsof adhesion and colloidal stability.

According to one preferred characteristic of the invention, the filler(D) consists of particles of hydrophilic compound(s) with a relativelyhigh specific surface area Ss, ie:

-   -   Ss>3        preferably Ss>5.

In accordance with the invention, the aqueous dispersion is alsocharacterized by excellent colloidal stability, reflected by a residualemulsion content T (%) measured according to a protocol P such that:

-   -   T≧70        preferably T≧80        and even more preferably T≧85

It was not in any way foreseeable that the use, in the form of acolloidal aqueous suspension, of a filler made of at least onehydrophilic compound, would give such values for T.

According to one advantageous characteristic of the invention, thedispersion draws its specificity from the fact that this (or these)aqueous suspension(s) of filler (D) is (are) introduced totally orpartially into the blending chamber before producing the emulsion; thefraction of suspension(s) of filler (D) that may be introduced beforeproducing the emulsion is between 2% and 100% and preferably between 3%and 100%, by dry weight of the total amount of filler (D) taken in dryform.

For example, when the filler (D) is CaCO₃ and when only one fraction ofthe aqueous colloidal suspension of filler (D) is introduced into thechamber for preparing the dispersion, before producing emulsion, thisfraction of filler (D) advantageously represents between 2% and 40% andpreferably between 3% and 30%, by dry weight of the total amount offiller (D) taken in dry form.

It will be understood that the characteristics for producing thedispersion vary according to the nature of the hydrophilic filler (D).

Another advantageous characteristic of the dispersion according to theinvention relates to the fact that all the water required to produce theemulsion comes from the aqueous suspension(s) supplying the filler (D).

Advantageously, the concentration of hydrophilic filler (D) in theaqueous colloidal suspension is between 1% and 90% by dry weight,preferably between 20% and 90% by dry weight and even more preferablybetween 50% and 90% by dry weight.

In point in fact, the solids content of this colloidal suspension alsodepends on the amount of water that it is desired to supply to thedispersion via the colloidal filler.

In practice and generally, the particle size of the hydrophiliccompounds constituting the filler (D) is between 0.0001 and 300 μm. Thisparticle size depends of course on the nature of the hydrophiliccompounds.

According to one preferred arrangement of the invention, the filler (D)is selected from the group of hydrophilic compounds comprising: CaCO₃,SiO₂, TiO₂, Al₂O₃/H₂O, emulsified organic (co)polymer(s) and mixturesthereof.

These hydrophilic compounds capable of constituting the solidparticulate filler (D) may be obtained by precipitation from a liquidand/or by grinding.

When it is a particulate filler (D) obtained by precipitation, it ispossible for said precipitation to take place from water. This thengives directly an aqueous colloidal suspension of filler (D), which maybe used for the preparation of the dispersion according to theinvention.

According to one variant, this suspension may be obtained byincorporating the pulverulent dry filler (D) into water.

Thus, “slurries” of precipitated CaCO₃ or of ground CaCO₃ exist, forexample.

As regards silica SiO₂, it may be colloidal silica, precipitation silicaor pyrogenic silica.

The term “colloidal silica” denotes a stable suspension ofdifferentiated, substantially spherical silica particles between 0.00001and 0.1 μm in size, and preferably between 0.001 and 0.05 μm.

Emulsified organic copolymers are more commonly known under the name“latex” or “nanolatex”. They are, for example, aqueous dispersions ofpolymer particles obtained from standard processes of emulsion(co)polymerization of one or more polymerizable organic monomers. Theseorganic monomers are preferably chosen from:

-   a): alkyl (meth)acrylates, the alkyl portion of which preferably    contains from 1 to 18 carbon atoms, in particular methyl acrylate,    ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl    acrylate, amyl acrylate, lauryl acrylate, isoamyl acrylate,    2-ethyl-2-hexyl acrylate, octyl acrylate, methyl methacrylate,    chloroethyl methacrylate, butyl methacrylate, 3,3-dimethylbutyl    methacrylate, ethyl methacrylate, isobutyl methacrylate, isopropyl    methacrylate, phenyl methacrylate, butyl chloroacrylate, methyl    chloroacrylate, ethyl chloroacrylate, isopropyl chloroacrylate and    cyclohexyl chloroacrylate;-   b): α,β-ethylenically unsaturated esters of monocarboxylic acids,    the acid portion of which is unpolymerizable, and the unsaturated    portion of which preferably contains from 2 to 14 carbon atoms and    the acid portion of which contains from 2 to 12 carbon atoms, in    particular vinyl acetate, vinyl propionate, vinyl butyrate, alkyl    acetate, vinyl versatate® (registered trademark for C₉–C₁₁    α-branched acid esters), vinyl laurate, vinyl benzoate, vinyl    trimethylacetate, vinyl pivalate and vinyl trichloroacetate;-   c): esters and hemiesters of α,β-ethylenically unsaturated    polycarboxylic acids containing from 4 to 24 carbon atoms, in    particular dimethyl [lacuna], diethyl maleate, methyl ethyl fumarate    and 2-ethylhexyl fumarate;-   d): vinyl halogens, in particular vinyl chloride, vinyl fluoride,    vinylidene chloride and vinylidene fluoride;-   e): vinylaromatics preferably containing not more than 24 carbon    atoms and chosen in particular from styrene, α-methylstyrene,    4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene,    2-hydroxymethylstyrene, 4-ethylstyrene, 4-ethoxystyrene,    3,4-dimethylstyrene, 2-chlorostyrene, 3-chlorostyrene,    4-chloro-3-methylstyrene, 4-tert-butylstyrene, 4-dichlorostyrene,    2,6 -dichlorostyrene, 2,5-difluorostyrene and 1-vinylnaphthalene;-   f): conjugated aliphatic dienes preferably containing from 3 to 12    carbon atoms, in particular 1,3-butadiene, isoprene and    2-chloro-1,3-butadiene;-   g): α,β-ethylenically unsaturated nitriles preferably containing    from 3 to 6 carbon atoms, such as acrylonitrile and    methacrylonitrile.

It is also possible to copolymerize at least one of the main monomers a)to g) with up to 40% by weight of at least one other monomer of ionicnature, in particular:

-   an α,β-ethylenically unsaturated carboxylic acid monomer mentioned    above, including monocarboxylic and polycarboxylic acids (acrylic    acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid,    etc.),-   an ethylenic monomer comprising secondary, tertiary or quaternized    amine groups (vinylpyridines, diethylaminoethyl methacrylate, etc.),-   a sulfonated ethylenic monomer (vinylsulfonate, styrenesulfonate,    etc.),-   a zwitterionic ethylenic monomer (sulfopropyl-(dimethylaminopropyl)    acrylate) or an ethylenic monomer of nonionic nature, in particular,-   unsaturated carboxylic acid amides (acrylamide, methacrylamide,    etc.),-   esters of (meth)acrylates and of polyhydroxypropyl or    polyhydroxyethylated alcohols,-   vinylsilanes and/or acrylic silanes (such as vinyl-trimethoxysilane    and vinyltriethoxysilane).

According to one variant, the dispersions according to the invention maycomprise, in addition to the hydrophilic filler (D) supplied in the formof an aqueous colloidal suspension, a filler (D′) that is involved inthe process for obtaining the dispersion, in pulverulent form. Thisfiller (D′) supplied in powder form to the mixture leading to thedispersion differs from the dry hydrophilic filler (D) in terms of itssmaller specific surface area Ss (m²/g), ie:

-   -   Ss≦5        preferably Ss≦3.

Examples of pulverulent fillers (D′) that may be mentioned include:CaCO₃, SiO₃, TiO₂, Al₂O₃/H₂O.

Advantageously, the filler (D′) may represent 5 to 100 parts by dryweight per 100 parts by weight of silicone phase φs.

As regards the silicone phase (φs), and in particular the essentialconstituent(s) thereof: the oil(s) (A), it is important to note that, inaccordance with the invention, oils (A) of specific nature and viscosityhave been selected.

The dynamic viscosity of the oil (A) and thus of the silicone phase φsis greater than or equal to 10 Pa.s, preferably greater than or equal to50 Pa.s and more preferably greater than or equal to 70 Pa.s. Thisviscosity is an important parameter of the invention. This parameter maybe determined, for example, using a Brookfield viscometer according toAFNOR standard NFT 76 102 02 February 1972.

Advantageously, the oils (A) are α,ω-hydroxylated oils or functionaloils comprising, per molecule, at least 2 functional groups that may becondensed optionally after hydrolysis.

Even more specifically, these oils (A) may be represented by the generalformula (I) below:

in which formula:

-   a is 0 or 1-   b is 0 or 1-   with a+b=0; 1 or 2-   n has a value that is sufficient to give the polymer of formula (a)    the desired viscosity-   the radicals R are identical or different and represent    -   an OH group with a+b=2;    -   an alkoxy or alkenyloxy group containing from 1 to 10 carbon        atoms;    -   an aryloxy group containing from 6 to 13 carbon atoms;    -   an acyloxy group containing from 1 to 13 carbon atoms;    -   a ketiminoxy group containing from 1 to 8 carbon atoms;    -   a an amino-functional or amido-functional group containing from        1 to 6 carbon atoms, linked to the silicon via an Si—N bond;-   the radicals R¹ and R² are identical or different and represent    alkyl or alkenyl aliphatic organic groups containing from 1 to 10    carbon atoms, or phenyl aromatic groups, said groups optionally    being substituted with halogen atoms or cyano groups;-   the radicals R³ and R⁴ are identical or different and represent    alkyl, aminoalkyl, polyaminoalkyl, epoxyalkyl or alkenyl aliphatic    organic groups, containing from 1 to 13 carbon atoms, or aryl    aromatic groups containing from 6 to 13 carbon atoms; at least 2    functional groups that may be condensed optionally after hydrolysis    being present per molecule of at least 80% of the radicals R¹ to R⁴    representing a methyl group.

Examples of radicals R that may be mentioned include the followinggroups:

-   -   alkoxy such as, for example, methoxy, ethoxy or octyloxy;    -   alkenyloxy such as, for example, vinyloxy, hexenyloxy or        isopropenyloxy;    -   aryloxy such as, for example, phenyloxy;    -   acyloxy such as, for example, acetoxy;    -   ketiminoxy such as, for example, ON═C(CH₃)C₂H₅;    -   amino-functional groups such as, for example, ethylamino or        phenylamino;    -   amido-functional groups such as, for example, methylacetamido.

Among the aliphatic or aromatic organic radicals mentioned above,mention may be made of, as regards

-   -   R¹, R²: for example, methyl, ethyl, octyl, trifluoropropyl,        vinyl and phenyl groups;    -   R³, R⁴: for example, methyl, ethyl, octyl, vinyl, allyl and        phenyl groups;        —(CH₂)₃—NH₂; —(CH₂)₃—NH—(CH₂)₂—NH₂;

As concrete examples of units D: R¹R²SiO_(2/2) present in the oil (A),mention may be made of:

-   (CH₃)₂SiO_(2/2); CH₃(CH₂═CH)SiO_(2/2); CH₃(C₆H₅)SiO_(2/2);    (C₆H₅)₂SiO_(2/2)

As concrete examples of units M: RR³R⁴SiO_(1/2), mention may be made of:

-   (CH₃)₂(OH)SiO_(1/2); (OCH₃)₃SiO_(1/2); [O—C(CH₃)═CH₂]₃SiO_(1/2)    [ON═C(CH₃)]₃SiO_(1/2); (NH—CH₃)₃SiO_(1/2); (NH—CO—CH₃)₃SiO_(1/2).

A crosslinking agent (B) must be used when the oil (A) is anα,ω-(dihydroxy)polydiorganosiloxane polymer.

Many crosslinking agents may be used in amounts that depend on theirnature; these agents are well known to those skilled in the art.

A list of crosslinking agents will be found hereinbelow, by way ofexample, with the recommended corresponding amounts, expressed as partsby weight per 100 parts of oil (A):

-   -   0.5 to 10 parts of sodium silicate    -   0.1 to 15 parts of an alkali metal organosiliconate (European        patent EP-A-266 729)    -   1 to 100 parts of a microemulsion of silsesquioxane resin        (patents U.S. Pat. Nos. 3,355,406; 3,433,780)    -   5 to 100 parts of a reactive silicone resin of low molecular        mass containing alkoxy and acyloxy groups (U.S. Pat. No.        4,554,187)    -   5 to 100 parts of a silicone resin of high mass, which is        insoluble in toluene (EP-A-304 719)    -   5 to 100 parts of a hydroxylated silicone resin consisting of        units of formulae R′₃SiO_(1/2) (M) and/or R′₂SiO_(2/2) (D),        combined with units of formula R′SiO_(3/2) (T) and/or SiO₂(Q),        R′ mainly being a C₁–C₆ alkyl, vinyl or 3,3,3-trifluoro-propyl        radical, and a weight content of hydroxyl group of between 0.1        and 10%. Among these resins, mention may be made most        particularly of the resins MQ, MDQ, TDM and TD (FR-A-2 638 166).    -   1 to 20 parts of a silane of formula:        (R″)_(u)SiX_((4−u))    -   in which formula R″ is a monovalent organic radical, in        particular methyl or vinyl, u is equal to 1 or 0, X is a        condensable and/or hydrolyzable organic group of the same        definition as the radical R of formula (I) above (alkoxy,        alkenyloxy, acyloxy, ketiminoxy, alkylamino or alkylamido        silanes described especially in U.S. Pat. Nos. 3,294,725;        4,584,341; 4,618,642; 4,608,412; 4,525,565; EP-A-387 157;        EP-A-340 120; EP-A-364 375; FR-A-1 248 826; FR-1 023 477).

Examples that may be mentioned include the following alkoxysilanes:

-   -   Si(OC₂H₅)₄; CH₃Si(OCH₃)₃; CH₃Si(OC₂H₅)₃;    -   (C₂H₅O)₃Si(OCH₃); CH₂═CHSi(OCH₃)₃;    -   CH₃(CH₂═CH)Si(OCH₃)₂; CH₂═CH(OC₂H₅)₃;    -   CH₂═CHSi[ON═C(CH₃)C₂H₅]; CH₃Si[ON═C(CH₃)₂]₃;    -   CH₃Si[—C(CH₃)═CH₂]₃;    -   methyltri (N-methylacetamidosilane);        methyltris-(cyclohexylaminosilane).

The adhesion promoters (C) are preferably silanes. These silanes (C)optionally present in the composition of the dispersions of theinvention are additives that make it possible to modify thephysicochemical properties of the silicone elastomer compositionsobtained after crosslinking the dispersions forming the subject of theinvention.

The silanes obtained as by-products of the reaction for the synthesis ofthe oils (A) may be represented by the formula: (R⁵)_(c)Si(R)_(4−c)

in which formula:

-   c is 0; 1 or 2-   the radicals R⁵, which may be identical or different, correspond to    the radicals R³ and R⁴ of the oil (A) of formula (I)-   the radical R corresponds to the organic radical R of the    polyorganosiloxane oil (A) of formula (I).

Examples of such silanes that may be mentioned include the crosslinkingsilanes mentioned above. They are generally present in amounts of aboutfrom 0 to 10 parts by weight, and preferably of about from 0 to 5 partsby weight, per 100 parts of oil(s) (A).

The silane additives for modifying the physicochemical properties mayespecially be adhesion agents such as those described in patentapplication EP-A-340 120. Mention may be made especially ofaminopropyltriethoxysilane, aminopropylmethyldiethoxy-silane andglycidoxypropyltrimethoxysilane. They are used in amounts that may be upto 50%, generally of about from 0.5% to 10%, of the weight of oil(s)(A).

Catalytic curing compounds (E) are well known to those skilled in theart; they are carboxylic acid salts and halides of metals such as, forexample, lead, zinc, zirconium, titanium, iron, barium, calcium,manganese and, most particularly, tin.

Mention may be made of:

-   -   the products of reaction of tin dicarboxylates and of polyethyl        silicate (U.S. Pat. No. 3,862,919),    -   the products of reaction of dibutyltin diacetate and of an alkyl        silicate or of an alkyltrialkoxysilane (BE-A-842 305),    -   tin bischelates (EP-A-147 323; 235 049),    -   diorganotin dicarboxylates (GB-A-1 289 900).

They may be used in amounts that may be up to about 3 parts by weight,preferably in the region of 0.05 to 1 part by weight, per 100 parts ofoil (A).

The emulsifiers (F) used may be ionic or nonionic surfactants orwater-soluble polymers.

They are preferably nonionic surfactants. Examples that may be mentionedinclude alkoxylated fatty acids, polyalkoxylated alkylphenols,polyalkoxylated fatty alcohols, polyalkoxylated or polyglycerolatedfatty amides, polyglycerolated alcohols and α-diols, ethyleneoxide/propylene oxide block polymers and also alkylglucosides,alkylpolyglucosides, sucroethers, sucroesters, sucroglycerides, sorbitanesters and ethoxylated compounds of these sugar derivatives.

According to one variant, the emulsifiers (F) are selected from anionicsurfactants such as, for example, alkylbenzene sulfonates, alkylsulfates, alkyl ether sulfates, alkylaryl ether sulfates and dioctylsulfosuccinates, of alkali metals.

The (mixture of) emulsifier(s) is chosen as a function of the nature ofthe silicone oil (A) to be emulsified; an HLB value of about 11 to 15 isgenerally chosen to emulsify a silicone oil (A) consisting of anα,ω-bis(hydroxy)polydimethylsiloxane polymer. Thewater/water+emulsifier(s) (F) weight ratio depends on the viscosity ofthe silicone phase (φs) and on the nature of the (mixture of)surfactant(s); this ratio is, for example, from about 20/100 to 70/100,preferably from about 25/100 to 60/100, to stabilize an emulsion of asilicone phase consisting of an α,ω-dihydroxylated oil with a viscosityfrom about 30 to 500 Pa.s, using a nonylphenol containing 9 or 10 ethoxyunits as sole emulsifier (F).

According to one particular embodiment of the invention, the aqueoussilicone dispersion is obtained by using a colloidal silica dispersion(D) is at least one nonionic surfactant (F), this colloidal silica andthis or these nonionic surfactant(s) being incorporated into the mixtureat least partially during the emulsification so as to facilitate saidemulsification.

In practice, the silicone phase (φs) consists of:

-   (φs1) an oil (A) with a viscosity of at least 10 Pa.s,-   (φs2) a mixture of oils (A), this mixture having a viscosity of at    least 10 Pa.s,-   (φs3) a mixture of at least one oil (A) and of at least one    crosslinking agent (B) if the latter is necessary and/or a silane    (C), this mixture having a viscosity of at least 10 Pa.s,-   or (φs4) a mixture of at least one oil (A) and of the catalytic    compound (E), optionally in the presence of at least one silane (C).

Even more preferably, the silicone phase φs consists of:

-   (φs1) an oil (A) with a viscosity from about 50 to 1 000 Pa.s,-   (φs2) a mixture of oils (A), this mixture having a viscosity from    about 50 to 1 000 Pa.s,-   (φs3) a mixture of at least one oil (A) and of at least one    crosslinking agent (B) if the latter is necessary and/or a silane    (C), this mixture having a viscosity from about 50 to 1 000 Pa.s,-   or (φs4) a mixture of at least one oil (A) and of the catalytic    compound (E), optionally in the presence of at least one silane (C).

As regards other functional additives (G) that may be used, they areespecially plasticizers and/or salts and/or thickeners and/or fillerdispersants, the latter agents preferably being selected from the groupof anionic hydrophilic functional products and even more preferably fromthe group comprising polyacrylates and/or (poly)phosphates.

These additives may also or more specifically be:

-   -   plasticizers such as, for example, polydimethylsiloxane oils        with a viscosity from about 300 to 10 000 mPa.s,        dioctylphthalates, dialkylbenzenes optionally in aqueous        emulsion, in amounts from 0 to 70 parts by weight per 100 parts        by weight of oil (A);    -   thickeners, for instance water-soluble polymers of molecular        weight greater than 10 000 g/mol, such as, for example, alkali        metal polyacrylates, polyvinyl alcohols, polyethylene glycols,        polyvinylpyrrolidones, carrageenans, alginates,        methylcelluloses, hydroxyalkylcelluloses and xanthan gum in        amounts that may be up to 10% by weight of the final aqueous        dispersion;    -   filler dispersants such as, for example, alkali metal        polyacrylates of molecular mass less than 5 000, and mineral        phosphates in amounts that may be up to 10% by weight of the        final aqueous dispersion;    -   optionally, mineral or organic pigments in an amount of less        than 4% and preferably 2% by weight relative to the total mass        of the dispersion.

These additives (G) may be introduced either into the silicone phasebefore it is emulsified, or into the emulsion before dilution.

According to another of its aspects, the present invention relates to aprocess for preparing an aqueous dispersion of silicone oils, especiallythose described above, which comprise:

-   A—100 parts by weight of oil(s) (A) of at least one    organopolysiloxane oil (A) capable of crosslinking into an elastomer    by condensation, if necessary in the presence of a crosslinking    agent (B);-   B—if necessary, from 0.1 to 100 parts by weight of at least one    crosslinking agent (B);-   C—optionally, up to 50 parts by weight of at least one adhesion    promoter (C)—preferably a silane—;-   D—up to 200 parts by dry weight of a siliceous mineral filler (D);-   E—a catalytically effective amount of a catalytic curing compound    (E), which may be up to 3 parts by weight;-   F—at least one emulsifier (F);-   G—at least one functional additive (G);-   H—and water; this process comprising the following essential steps:-   I—preparation of an emulsion by blending a mixture consisting of:    -   100 parts by weight of a silicone phase (φs) with a dynamic        viscosity at 25° C. of at least 10 Pa.s, this silicone phase        comprising the oil or mixture of oils (A) already polymerized,        and optionally at least one of the constituents (B), (C) or (E);    -   0.5–20 parts by weight of at least one emulsifier (F), the HLB        value of said emulsifier or of the mixture of emulsifiers being        at least 10;    -   2–20 parts by weight of water; the water/water+emulsifier(s)        weight ratio being such that the viscosity of the        water+emulsifier(s) mixture is in the region of or greater than        half that of the silicone phase (φs);    -   for a period and under shear conditions that are sufficient to        obtain an “oil-in-water” emulsion with a particle size from        about 0.1 to 5 micrometers;-   II—optional dilution with water until a solids content from 25% to    97% is obtained;-   III—and then addition of the constituent(s) not    -   present in the silicone phase (φs); this process being        characterized in that at least one substep of incorporation of a        filler (D) in the form of (an) aqueous suspension(s) of at least        one hydrophilic compound is envisioned, with the conditions        according to which:    -   when this filler (D) consists at least partly of at least one        aqueous suspension of colloidal silica, then this (or these)        aqueous suspension(s) of filler (D) is (are) introduced in total        into the blending chamber before producing the emulsion;    -   when this filler (D) consists at least partly of an aqueous        suspension of organic (co)polymer(s), then at least some of this        (or these) aqueous suspension(s) of filler (D) is (are)        introduced into the blending chamber before producing the        emulsion.

The process according to the present invention preferably has all thecharacteristics given above with reference to the description of theaqueous silicone dispersions according to the invention.

According to one preferred and specific mode of the process according tothe invention, the substep(s) of incorporating the aqueous suspension(s)of filler (D) take(s) place:

-   -   during step I in a fraction of between 2% and 100%, and        preferably between 3% and 100% by dry weight of the total amount        of filler (D) in dry form;    -   and during step II and/or III, preferably III.

Thus, the moment(s) for introduction of the aqueous suspension ofhydrophilic filler (D) is (are) chosen as a function of the reologicaland/or mechanical characteristics that it is desired to obtain for theaqueous silicone dispersions according to the invention, and as afunction of the nature of the hydrophilic filler (D).

In accordance with the invention, at least some of the water is providedby the aqueous dispersion of hydrophilic filler (D).

It is particularly advantageous to control the amount of water suppliedto the aqueous silicone dispersion, by means of the liquid fillerconstituent.

Advantageously, the “oil-in-water” emulsification of the silicones phaseis performed:

-   -   by introducing the silicone oil (A) into a mixture of water        and/or aqueous suspension(s) of filler (D)+emulsifier(s) (F);    -   or by introducing water and/or aqueous suspension(s) of        filler (D) into a mixture of silicone phase        (φs)+emulsifier(s) (F) and blending at a temperature from about        10 to 50° C.

Any standard blending machine may be used, especially slow stirringmachines. Thus, the blending operation may be performed in a blenderequipped with a stirrer, the mobile part of which stirrer does not torotate:

-   -   at more than 2500 rpm with a tangential speed at the end of the        mobile part not exceeding 20 m/s; and a ratio of the tangential        speed at the end of the mobile part to the distance between the        end of the mobile part and the wall of the blender, of less than        50 000 s⁻¹;    -   at more than 1500 rpm with a tangential speed at the end of the        mobile part not exceeding 5 m/s and a ratio of the tangential        speed at the end of the mobile part to the distance between the        end of the mobile part and the wall of the blender, of less than        10 000 s⁻¹;    -   at more than 500 rpm with a tangential speed at the end of the        mobile part not exceeding 2.5 m/s and a ratio of the tangential        speed at the end of the mobile part to the distance between the        end of the mobile part and the wall of the blender, of less than        2500 s⁻¹.

Examples that may be mentioned include single-screw or multi-screwextruders, planetary blenders, hook blenders, slow dispersers, staticblenders, paddle blenders, impeller blenders, arm blenders and anchorblenders.

After optional dilution of the medium, the constituents of thedispersion of the invention not present in the “oil-in-water” emulsionthus prepared, namely:

-   -   in the case of the emulsion of the silicone phase (φ1) , (φ2) or        (φ3), the catalytic compound (E) preferably in the form of an        aqueous emulsion and the other optional constituents not present        in said phases;    -   in the case of the emulsion of the silicone phase (φ4), the        crosslinking agent (B) if the latter is necessary, and also the        other optional constituents not present in said phase;    -   and, in all cases, an optional suspension of filler (D);        are introduced into and dispersed in the medium by blending in a        blender (step III) of the same type as those mentioned above,        preferably in the blender used for the emulsification (step I).

The various constituents of the dispersion of the invention are presentin amounts such that the solids content is greater than 40%, generallyfrom about 70% to 97%; the pH is adjusted to between 4 and 13 byaddition of organic or mineral acids or bases (for example potassiumhydroxide or amines).

The final dispersion obtained is homogenized and then degassed; it isthen packaged in airtight and water vapour-proof packaging.

Advantageously, this process comprises at least one substep ofincorporating a filler (D′) in pulverulent form, which has a specificsurface area Ss (in m²/g) such that:

-   -   Ss≦5

preferably Ss≦3

Finally, the present invention is directed toward the use of the aqueoussilicone dispersions described above, in unmodified form or as productsobtained by the process also defined above, for the manufacture ofelastomeric paints, water-repellent paints for facades, leakproofingseals, flame-retardant elastomeric products, concentrated mastics,elastomeric coating products, water-repellent or flame-retardantprotective coverings that may be sprayed (as a thin or thick layer) andalso coverings for use in roofing (i.e. silicone elastomer coverings onpolymer foams (for example two-pack polymethane) used especially forinsulating the roofs of buildings.

According to another of its subjects, the invention also relates to aconcentrated mastic based on the dispersion described above. This masticis characterized in that it has a solids content of greater than orequal to 80% by weight and preferably greater than or equal to 85% byweight.

To prepare such a concentrated mastic, it is advantageous to use anaqueous colloidal suspension of filler (D) having a titer of 40%–85% byweight of (D) relative to the solids, and preferably from 65% to 80% byweight of (D) relative to the solids.

The examples are given as a guide and cannot be considered as limitingthe field and spirit of the invention.

EXAMPLES Example 1 Paint/Film-forming Covering Formulation with AqueousDispersion (“Slurry”) of CaCO₃

I—Preparation of the Emulsion:

Introduction of 33.5 kg of 48 V 135000 oil (A) from Rhodia Silicones(α,ω-dihydroxylated poly-dimethylsiloxane silicone oil, viscosity=135000mPa.s, with a titer of about 300 ppm of OH by weight), 1.843 kg of ahydroxylated silicone resin—crosslinking agent (B)—(Resin (B) fromRhône-Poulenc, containing MDT units, with 0.5% by weight of OH groups,and consisting of 62% by weight of units T (CH₃SiO_(3/2)), 24% by weightof units D [(CH₃)₂SiO_(2/2)] and 14% by weight of units M[(CH₃)₃SiO_(1/2)], 1.575 kg of Rhodasurf ROX—surfactant (F)—(aqueoussolution containing 85% ethoxylated fatty alcohol from Rhodia) and 0.52kg of demineralized water (H) into the tank of a 100 liter Neulingerbutterfly-type planetary blender (equipped with a stirrer) and aplanetary dispersion arm, and also a scraping stirrer. Stirring for 60minutes at a speed of 400 rpm for the butterfly and 42 rpm for thedoctor blade. Production of a silicone/water emulsion with a meanparticle size of 567 nm (measured using a Coulter LS 130 machine fromthe company Coultronics). The bulk temperature reaches 45° C.

II—Gradual dilution of the emulsion by introducing over 15 minutes12.507 kg of demineralized water (H) with stirring (butterfly at 400 rpmand doctor blade at 21 rpm).

III—Compounding:

The temperature is 35° C. After reducing the stirring speed of thebutterfly, introduction over 2 min of 1 kg of Silquest VS 142 fromWitco—adhesion promoter (C)—(aqueous solution containing about 25% ofamino silane) and, over 15 minutes, 46.9 kg of an aqueous dispersioncontaining 72% of CaCO₃ filler (D) (Omyacoat 80 from the company Omya).The temperature is 29° C.

Finally, 0.109 kg of an aqueous emulsion with a titer of 38% ofdioctyltin dilaurate stabilized with polyvinyl alcohol—catalyst(E)—(emulsion 70827 A from Rhodia) is added, and stirred for a further15 minutes, the speeds of the butterfly and the doctor blade being 200and 42 rpm, respectively.

The composition is then degassed by stirring under the same conditionsfor 10 minutes under a vacuum of 150 mbar, then packaged in 25 kg pails(metallic and Epikote-treated) and in water vapour-proof polyethylenecartridges. It has a solids content of 72%.

The results of the evaluation of the product obtained are given in table1.

Evaluation Methods:

Protocol for Measuring the Degree of Coalescence T of the Emulsion inthe Mastic:

The content of residual emulsion in the final product is determinedaccording to protocol P below: a 10% dilution of the product indemineralized water is prepared, by stirring with a magnetic bar for 20minutes. The dilute product is rapidly transferred into a centrifugationbucket and centrifuged for 30 minutes at 3000 rpm in a Heraeus Chris1729/1800 centrifuge in order to separate out the solid fillers. Thenonsolid phase (emulsion) is withdrawn and its solids content ismeasured by drying in a Mettler infrared thermobalance (4 g dried for 1hour with a nominal temperature of 120° C.). The solids content of thedilute emulsion thus measured is then compared with the theoreticalsolids content calculated from the composition by assuming that theinitial emulsion is intact and by integrating the degree of dilution. Ifthe emulsion is not broken during the formulation with the fillers, theresidual emulsion content is 100%; when a total coalescence of theemulsion has taken place during blending with the fillers this contentis zero. The residual emulsion content is defined by the relationship:T(%)=100×(measured solids content)/(theoretical solids content)

The content of emulsion coalesced (or broken) during mixing with thefillers is C (%)=100−T

NB: it was verified that by applying the protocol to an emulsion notblended in the presence of fillers, the measurement makes it possible tofind the theoretical solids content, i.e. T=100% of residual emulsion.

Measurement of the Mechanical Properties:

The mastic is spread as a 2 mm film (using a calibrated doctor blade)over a nonstick terphane sheet so as to be able to measure after drying(seven days in an air-conditioned room at 23° C. and 50% RH) thefollowing mechanical properties:

-   the Shore A hardness according to ASTM standard D-2240 (on three    stacked 2 mm films)-   the breaking strength (in MPa) according to AFNOR standard T 46 002    corresponding to ASTM standard D 412,-   the elongation at break (in %) according to AFNOR T 46 002,-   the elastic modulus at 100% elongation (in MPa) according to AFNOR    standard T 46 002.    Evaluation of the Adhesion:

Finally, the adhesion of the mastic to various supports (glass,aluminum, PVC, etc.) is assessed by manual peeling of a film 0.5 mmthick dried for 14 days on the test support.

Comparative Example 2 Paint/Film-forming Covering Formulation withHydrophobic CaCO₃

-   I—Preparation of the emulsion: the emulsion according to example 1    is again prepared, and the mean particle size of the emulsion    obtained is very similar (550 nm, at a temperature of 41.5° C.).-   II—this emulsion is diluted (in the same blender as previously) with    16.72 kg of demineralized water (added gradually over 15 minutes,    butterfly at 400 rpm and doctor blade at 21 rpm, the temperature    decreases to 31° C.).-   III—Compounding: 0.804 g of Coatex P50 from the company Coatex    (dispersant (G) based on sodium polyacrylate) and 1 kg of Silquest    VS142 adhesion promoter=silane (C) are added (these two additives    are introduced over two minutes each), with the butterfly at 200 rpm    and the doctor blade at 21 rpm. After switching off the stirring,    12.56 kg of Socal 312 (treated precipitated CaCO₃ from Solvay, with    a specific surface area of 20 m²/g) are added and dispersed for two    minutes with the butterfly at 200 rpm and the doctor blade at 42    rpm. After stopping the mixer again, 12.56 kg of Socal 312 are added    and dispersed as above by stirring for two minutes. 16.75 kg of BLR3    (treated natural CaCO₃ from the company Omya, with a low specific    surface area) are then added and dispersed as above by stirring for    four minutes. After reducing the speed of the scraping stirrer to 21    rpm, 12.28 kg of demineralized water are then added over 10 minutes,    followed by addition of 0.109 kg of emulsion 70827A over one minute,    and stirring is continued for about a further 10 minutes to obtain a    thoroughly homogeneous mixture. The final product is degassed by    stirring for five minutes under a vacuum of 100 mbar, and is then    packaged in 25 kg pails and in polyethylene cartridges. The solids    content of the final product is 71.7%.

The results of the evaluation of the product obtained are collated intable 1.

Comparative Example 2a Paint/Film-forming Covering Formulation withPowdered Hydrophilic CaCO₃

-   I—Preparation of the emulsion: the emulsion according to example 1    is again prepared, and the mean particle size of the emulsion    obtained is very similar (560 nm, at a temperature of 42° C.).-   II—this emulsion is diluted (in the same blender as previously) with    16.72 kg of demineralized water (added gradually over 15 minutes,    butterfly at 400 rpm and doctor blade at 21 rpm, the temperature    decreases to 31° C.).-   III—Compounding: comparative example 2 is repeated, but replacing    the 25 kg of Socal 312 with 13.4 kg of Socal 31 from Solvay (which    has the same specific surface area of 20 m²/g, but is not treated    with stearic acid). The solids content of the final product is    68.4%.

The results of the evaluation of the product obtained are collated intable 1.

TABLE 1 Example 2 Example 2a Example 1 (hydrophobic (hydrophilic (slurryof CaCO₃ in CaCO₃, in CaCO₃) powder form) powder form) Residual emulsion88.8% 37% 65% content T Coalesced emulsion 11.2% 63% 35% content CBrookfield viscosity 56 46.4 28.4 A7V5 (Pa · s) Appearance of the 2Smooth Slightly Granular mm films granular Mechanical propertiesmeasured after 15 days in a cartridge and drying for 7 days: Hardness(Shore A) 28 45 28 Breaking strength (MPa) 1.27 0.85 0.63 Elongation atbreak (%) 902 427 180 Modulus at 100% 0.38 0.57 0.33 elongation (MPa)Mechanical properties measured after 3 months in a cartridge and dryingfor 7 days Hardness (Shore A) 29 Not measurable 29 (poorly cohesivefilm) Breaking strength (MPa) 0.60 Not measurable 0.63 (poorly cohesivefilm) Elongation at break (%) 356 Not measurable 200 (poorly cohesivefilm) Modulus at 100% 0.43 Not measurable 0.5 elongation (MPa) (poorlycohesive film) Application using an Smooth Degraded Impossible airlessgun film appearance Adhesion to PUR foam Good Mediocre Average(evaluated by manual peeling)

It emerges from the previous tests that the use of carbonate inpredispersed form—CaCO₃ colloidal suspension filler (D)—makes itpossible, compared with the control produced with powdered hydrophobicCaCO₃, to preserve the quality of the emulsion, which has a directinfluence on the properties of the final product: more attractiveappearance, better mechanical properties and adhesion, betterconservation on storage, and better resistance during use (pressurizedspraying). With hydrophilic carbonate introduced in powder form, thereis less degradation of the emulsion than with hydrophobic carbonate(partly because a smaller dose of carbonate was used); however, thegranular appearance of the film obtained on drying is unacceptable, theelastomer has a smaller elongation at break, and the wet product couldnot be applied using an airless gun (clogging).

Example 3 Mastic Based on CaCO₃ Slurry Introduced During Emulsification

Introduction of 465 g of oil—(A)—48V135 000; 35 g of oil—(A)—47V100 fromRhodia (polydimethylsiloxane oil with a viscosity of 100 mPa.s), 5 g ofresin/crosslinking agent—(B)—, 23.5 g of Rhodasurf ROX—(F)—and 27.5 g ofOmyacoat—(D)—80, into the tank of a laboratory IKA reactor equipped witha scraping anchor stirrer. By stirring at 80 rpm, an oil/water emulsionis rapidly obtained, but the stirring is continued for 45 minutes inorder to thoroughly refine and homogenize the aqueous dispersion. Afterintroduction of a further 625 g of Omyacoat 80—(D)—, stirring iscontinued for a further 25 minutes, followed by addition (with continuedstirring at the same speed) of 32.5 g of VS142—silane promoter (C)—(overfive minutes), 350 g of BLR3 (CaCO₃ of low specific surface area) (overfive minutes) and 1.8 g of 70827 A—emulsion (over five minutes). Thefinal mastic is degassed by stirring for five minutes under a vacuum of30 mbar and is then packaged in polyethylene cartridges. Throughout thetest, the temperature is maintained between 16 and 21° C. by circulatingcold water in the jacket of the mixer. The solids content of the finalproduct is 86.4%.

The characteristics and properties of the mastic are collated in table2.

The emulsification in the presence of predispersed filler offers thepossibility of producing concentrated dispersions with a low surfactantcontent (adhesive):

Example 4 (Comparative) Mastic Based on Powdered CaCO₃ (Socal312—Standard Formulation)

The objective of this comparative test is to repeat example 3, replacingthe CaCO₃ slurry with powdered CaCO₃ of high specific surface area, but,in order to prevent the coalescence of the emulsion (given the result ofthe comparative example 2), the surfactant content is increased andpolyacrylate dispersant is introduced. The coalescence test makes itpossible to show that, by means of this modification, the emulsion isnot disrupted by the addition of the pulverulent filler, but it hasreduced adhesion to the various supports targeted for the application ofthe product.

Performing the Test:

Introduction of 558 g of oil—(A)—48V 135 000, 42 g of oil—(A)—47V100from Rhodia (polydimethylsiloxane oil with a viscosity of 100 mPa.s), 6g of crosslinking resin (B)—, 42 g of Rhodasurf ROX—surfactant (F)—and13.2 g of demineralized water, into the tank of a laboratory IKA reactorequipped with a scraping anchor stirrer. By stirring at 80 rpm, anoil/water emulsion is rapidly obtained, but the stirring is continuedfor 40 minutes to allow a mean particle size of 0.5 pm to be obtained.The emulsion is diluted by gradual addition of 129.6 g of demineralizedwater—(H)—with stirring for 30 minutes. After reducing the stirringspeed to 60 rpm, 14.4 g of Coatex P50—polyacrylate dispersant (G)—(overfive minutes), 39 g of VS142—adhesion promoter=silane (C) (over fiveminutes), 300 g of Socal 312 powdered CaCO₃ (filler D′) (over tenminutes), 300 g of powdered CaCO₃ BLR3 of low specific surface area(filler D′) (over ten minutes) and 2 g of 70827 A—catalytic emulsion (E)(over five minutes) are successively introduced. The final mastic isdegassed by stirring for five minutes under a vacuum of 30 mbar and isthen packaged in polyethylene cartridges.

The solids content of the final product is 86.8%.

The characteristics and properties of the mastic are collated in table2.

Example 4a (Comparative) Mastic Based on Powdered Hydrophilic CaCO₃(Socal 31)

Example 4 is repeated, replacing the Socal 132 with Socal 31. Theproperties of the mastic were not measured, since it has a very granularappearance.

TABLE 2 Example 3 Example 4 (powdered (CaCO₃ slurry) treated CaCO₃)Residual emulsion content T 98% 97% Coalesced emulsion content C  2%  3%Boeing flowability (mm) 0 0 Appearance of the 2 mm films Smooth SmoothMechanical properties measured after 1 month in a cartridge and dryingfor 7 days: Hardness (Shore A) 23 16 Breaking strength (MPa) 0.92 0.65Elongation at break (%) 402 523 Modulus at 100% elongation 0.47 0.30(MPa) Adhesion evaluated by peeling after 1 month in a cartridge anddrying for 7 days on the support (silicone film 2 to 3 mm thick):Adhesion to glass Good Good Adhesion to wood Good Good Adhesion toanodized Good Good aluminum Adhesion to concrete Good Poor Adhesion toPVC Slight None Adhesion to PUR foam Good Mediocre

It emerges from these tests that, by increasing the dose of surfactant,the composition based on powdered CaCO₃ regains a high residual emulsioncontent, but at the expense of the adhesion, which on several supportsis poorer than that developed by the composition based on hydrophiliccarbonate slurry.

Example 5 Mastic Based on Colloidal Silica Introduced DuringEmulsification

Introduction of 480 g of oil (A)—48V135 000, 120 g (25%) of Progiline 55from Chevron—surfactant (F)—(alkylbenzene), 45 g (9.3%) of crosslinkingresin (B)—, 10.6 g (2.2%) of Rhodasurf ROX—surfactant (F)—and 150 g(31.25%) of Ludox TM50 from Dupont—liquid filler+powder (D) (aqueousdispersion of colloidal silica containing 50% (15.6%) of SiO₂) into thetank of a laboratory IKA reactor equipped with a scraping anchorstirrer. By stirring at 100 rpm, an oil/water emulsion is rapidlyobtained, but the stirring is continued for 1 hour 30 minutes in orderto thoroughly refine and homogenize the aqueous dispersion, the meanparticle size of which, determined using a Coulter 130 machine, is 1.85μm. This emulsion is diluted by gradual addition of 30.2 g ofdemineralized water over 10 minutes with stirring. 42 g of VS142—silanepromoter (C) are then added (over five minutes) (with continued stirringat the same speed), followed by addition of 3 g of 70827 A—catalyticemulsion (E)—(over five minutes). The final mastic is degassed bystirring for five minutes under a vacuum of 35 mbar and is then packagedin polyethylene cartridges. Throughout the test, the temperature ismaintained between 16 and 22° C. by circulating cold water in the jacketof the mixer.

The mean particle size of the final dispersion is 1.5 μm and its solidscontent is 84%.

The characteristics and properties of the mastic are collated in table3.

Example 6 Mastic Based on Colloidal Silica Introduced BeforeEmulsification

Introduction of 700 g of oil—(A)—48V135 000, 49 g of resin—crosslinkingagent (B)—12.4 g of Rhodasurf ROX—surfactant (F)—and 218.8 g of Snowtex40—filler (D) in suspension=from Nissan Chem. Ind. Ltd (aqueousdispersion of colloidal silica containing 40% of SiO₂) into the tank ofa laboratory IKA reactor equipped with a scraping anchor stirrer. Bystirring at 100 rpm, an oil/water emulsion is rapidly obtained, but thestirring is continued for 2 hours in order to thoroughly refine andhomogenize the aqueous dispersion, the mean particle size of which,determined using a Coulter 130 machine, is 2.85 μm. 45.5 g ofVS142—silane adhesion promoter (C)—are then added (over five minutes),followed by addition of 3.5 g of 70827 A—catalytic emulsion (E)—(overfive minutes). The final mastic is degassed by stirring for five minutesunder a vacuum of 37 mbar and is then packaged in polyethylenecartridges. Throughout the test, the temperature is maintained between19 and 25° C. by circulating cold water in the jacket of the mixer.

The mean particle size of the final dispersion is 1.3 μm and its solidscontent is 85.6%.

The characteristics and properties of the mastic are collated in table3.

Comparative Example 7 Mastic Based on Powdered Silica (Thixosil 365Test)

Introduction of 800 g of oil—(A)—48V 135 000, 24 g of resin—crosslinkingagent (B)—18.8 g of Rhodasurf ROX—surfactant (F)—and 40 g of LudoxTM50—liquid filler+powder (D)—into the tank of a laboratory IKA reactorequipped with a scraping anchor stirrer. By stirring at 100 rpm, anoil/water emulsion is rapidly obtained, but the stirring is continuedfor 2 hours in order to thoroughly refine and homogenize the aqueousdispersion, the mean particle size of which, determined using a Coulter130 machine, is 2.5 μm. The stirring speed is reduced to 60 rpm, theemulsion is diluted by adding 109.5 g of demineralized water, and 40 gof Thixosil 365 from Rhodia (powdered precipitated silica of highspecific surface area) are then introduced and dispersed for 20 minuteswith stirring. 52 g of VS142—adhesion promoter (C) are then added (overfive minutes), followed by addition of 2.6 g of 70827 A (over fiveminutes). The final mastic is degassed by stirring for five minutesunder a vacuum of 37 mbar and is then packaged in polyethylenecartridges. Its solids content is equal to 84%.

Throughout the test, the temperature is maintained between 20 and 26° C.by circulating cold water in the jacket of the mixer.

The characteristics and properties of the mastic are collated in table3.

TABLE 3 Example 5 Example 6 Example 7 Boeing flowability (mm) 0 0 —Appearance of the 2 mm Smooth Smooth — films Mechanical properties Theproduct still measured after 1 month extrudes from the in a cartridgeand cartridge, but it drying for 7 days: can no longer be spread with aspatula since it is elastic Hardness (Shore A) 10 19 Not measurableBreaking strength (MPa) 0.61 1.15 Not measurable elongation at break (%)379 494 Not measurable Modulus at 100% 0.20 0.34 Not measurableelongation (MPa) Adhesion evaluated by peeling after 1 month in acartridge and drying for 7 days on the support (silicone film 2 to 3 mmthick): Adhesion to glass Good Good Not measurable Adhesion to wood GoodGood Not measurable Adhesion to anodized Good Good Not measurablealuminum Adhesion to concrete Average Average Not measurable Adhesion toPVC Good Good Not measurable

Although formulated with a composition very similar to those of theprevious tests (content of surfactant and of reactive species), but witha powdered filler (D) of high specific surface area, the mastic ofexample 7 prepared with the powdered hydrophilic silica is not stable,and turns to a gel after storage for a few weeks in a cartridge at roomtemperature. In contrast, the compositions of examples 5 and 6 can bestored in a cartridge under the same conditions for more than one year.

1. A process for the preparation of an aqueous dispersion of silicone oil(s) comprising: 100 parts by weight of at least one polyorganosiloxane oil (A) capable of crosslinking into an elastomer by condensation, if necessary in the presence of a crosslinking agent (B); optionally, from 0.1 to 100 parts by weight of at least one crosslinking agent (B); optionally, up to 50 parts by weight of at least one adhesion promoter (C); greater than 0 up to 200 parts by dry weight of a filler (D); a catalytically effective amount of a catalytic curing compound (E); at least one emulsifier (F); optionally, at least one functional additive (G); and water; said process comprising the steps of: preparing an emulsion by blending a mixture consisting of: 100 parts by weight of a silicone phase (φs) with a dynamic viscosity at 25° C. of at least 10 Pa.s, φs comprising the oil or a mixture of oils (A) already polymerized, and optionally at least one of the constituents (B), (C) or (E); 0.5–20 parts by weight of at least one emulsifier (F), the HLB value of said emulsifier or of the mixture of emulsifiers being at least 10; the filler (D); 2–20 parts by weight of water; with a water/water and surfactant(s) weight ratio being such that the water and the surfactant(s) makes a mixture having a viscosity in the region of or greater than half that of the silicone phase (φs); for a period and under shear conditions that are sufficient to obtain an “oil-in-water” emulsion with a particle size from about 0.1 to 5 micrometers; optionally, diluting with water until a solids content from 25% to 97% is obtained; and, then, adding the constituent(s) not present in the silicone phase (φs) and the filler (D); the filler (D) being supplied in the form of (an) aqueous suspension(s) of at least one hydrophilic compound, with the proviso that: when the filler (D) is at least partly in the form of at least one aqueous suspension of colloidal silica, then this (or these) aqueous suspension(s) of filler (D) is (are) introduced into a blending chamber before producing the emulsion; or when the filler (D) is at least partly in the form of at least one aqueous suspension of organic (co)polymer(s), then at least some of this (or these) aqueous suspension(s) of filler (D) is (are) introduced into a blending chamber before producing the emulsion, said dispersion further comprising a filler (D′), which is added in the process for obtaining the dispersion, in pulverulent form, and whose specific surface area Ss (in m²/g) is: Ss≦5.
 2. The process as claimed in claim 1, wherein the oils (A) are α,ω-hydroxylated oils or functional oils comprising, per molecule, at least 2 functional groups.
 3. The process as claimed in claim 2, wherein the oils (A) have the general formula (I)

wherein: a is 0 or 1 b is 0 or 1 with a+b=0; 1 or 2 n has a value that is sufficient to give the polymer of formula (a) the desired viscosity the radicals R are identical or different and represent: an OH group with a+b=2; an alkoxy or alkenyloxy group containing from 1 to 10 carbon atoms; an aryloxy group containing from 6 to 13 carbon atoms; an acyloxy group containing from 1 to 13 carbon atoms; a ketiminoxy group containing from 1 to 8 carbon atoms; or an amino-functional or amido-functional group containing from 1 to 6 carbon atoms, linked to the silicon via an Si-N bond; the radicals R¹ and R² are identical or different and represent alkyl or alkenyl aliphatic organic groups containing from 1 to 10 carbon atoms, or phenyl aromatic groups, said groups optionally being substituted with halogen atoms or cyano groups; the radicals R³ and R⁴ are identical or different and represent alkyl, aminoalkyl, polyaminoalkyl, epoxyalkyl or alkenyl aliphatic organic groups, containing from 1 to 13 carbon atoms, or aryl aromatic groups containing from 6 to 13 carbon atoms.
 4. The process as claimed in claim 3, wherein at least 80% of the radicals R¹ to R⁴ represent a methyl group.
 5. The process as claimed in claim 3, wherein the adhesion promoter is a silane (c) of the formula: (R⁵)_(c)Si(R)_(4−c) wherein: c is 0; 1 or 2 the radicals R⁵, which are identical or different, correspond to the radicals R³ and R⁴ of the oil (A) of formula (I) the radical R corresponds to the organic radical R of the polyorganosiloxane oil (A) of formula (I) said silane being present in amounts of about from 0 to 10 parts by weight per 100 parts of oil(s) (A).
 6. The process as claimed in claim 1, wherein the crosslinking agent (B) is sodium silicate, an alkali metal organosiliconate, a microemulsion of silsesquioxane resin, a reactive silicone resin of low molecular mass containing alkoxy and acyloxy groups, a silicone resin of high mass, which is insoluble in toluene, a hydroxylated silicone resin, an alkoxysilane, an alkylaminosilane or an alkylamidosilane.
 7. The process as claimed in claim 1, wherein the the silane (C), is an adhesion-modifying additive and is aminopropyltriethoxysilane, aminopropylmethyldiethoxysilane or glycidoxypropyltrimethoxysilane, which is present in amounts of up to 50% of the weight of oil(s) (A).
 8. The process as claimed in claim 1, wherein the catalytic curing compound (E) is a tin derivative used in amounts of from 0.05 to 1 part by weight per 100 parts of oil (A).
 9. The process as claimed in claim 1, wherein the silicone phase (φs) consists of: (φs2) an oil (A) with a viscosity of at least 10 Pa.s, (φs2) a mixture of oils (A), this mixture having a viscosity of at least 10 Pa.s, (φs3) a mixture of at least one oil (A) and of at least one crosslinking agent (B) if the latter is necessary or a silane (C), this mixture having a viscosity of at least 10 Pa.s, or or (φs4) a mixture of at least one oil (A) and of the catalytic compound (E), optionally in the presence of at least one silane (C).
 10. The process as claimed in claim 9, wherein the silicone phase (φs) consists of: (φs1) an oil (A) with a viscosity from about 50 to 1 000 Pa.s, (φ2) a mixture of oils (A), this mixture having a viscosity from about 50 to 1 000 Pa.s, (φ3) a mixture of at least one oil (A) and of at least one crosslinking agent (B) if the latter is necessary and/or a silane (C), this mixture having a viscosity from about 50 to 1 000 Pa.s, or (φ4) a mixture of at least one oil (A) and of the catalytic compound (E), optionally in the presence of at least one silane (C).
 11. The process as claimed in claim 1, further comprising functional additives (G), plasticizers, thickeners, filler, or dispersants. 